Death registrations, laboratory confirmations, and hospital episode statistics
data indicated that 39 pertussis-related deaths occurred during 2002-2009; 30 were in patients with laboratory-confirmed pertussis.
To investigate this claim, we analyzed data for January 2000 through December 2010, using several national data sources: Hospital Episode Statistics
, routine laboratory reporting, death certificate data, and HIV surveillance data.
We compared NOIDS and laboratory reports to hospital episode statistics to determine the level of underreporting in each.
Significant underreporting of viral encephalitis was seen in the routine systems when compared to hospital episode statistics.
Excluding those cases for which no specific ICD-9 or ICD-10 code exists and which could not have been identified in hospital episode statistics, 558 cases of viral encephalitis were reported through the laboratory system from January 1, 1990, to March 31, 1998.
This study describes the epidemiology of viral encephalitis in England from 1989 to 1998 by using hospital episode statistics (available from: URL: http://www.
Hospital episode statistics record hospital admissions of viral encephalitis; although not timely enough for surveillance, these statistics can be used to monitor the distribution of admissions attributed to viral encephalitis by hospital physicians.
Why are so few diagnoses in hospital episode statistics specific?
In that comparative period, hospital episode statistics showed 259 deaths, only 42% of those formally certified and reported to the Office of National Statistics.
During our study of viral encephalitis in England, we found that more cases of viral encephalitis were identified in hospital episode statistics than in routine surveillance systems.
The coding system used for the hospital diagnoses recorded in hospital episode statistics changed from ICD-9 to ICD-10 beginning on April 1, 1995.